I found out that there are differences between the movie warren and the book warren, and that means also between sentinel eggs too. So dividing them in two parts again.
The Movie Warren:
We looked at the Bunny's realm as the ultimate birthplace of spring, a spiritual garden created to dazzle the senses with its colors and organic textures
- Hanenberger, p.61 of Arth of Rise of the Guardians.
This warren represents spring itself, and it’s located under Australia. Everything is covered in green and various colors, every plant in this warren has its purpose.
First are the flowers (tulips) that create googies. Googies are the egglets that will be painted and are those which the children search in the egg hunt during Easter Sunday.
Then there are the spray plants that give the googies the base color, that is blue, pink, green, yellow and similar. The egglets walk down the road and take the dip in the color river, where they become multicolored and shiny, till they pass in the vines to get decorated with various shapes.
The last step for the googies is going to the entries of the big tunnels that are divided by continents and then in smaller tunnels all around the globe, to be hidden on the surface for children to find them. In the artbook it's explained that it's important that the eggs' production process is completely organic.
The sentinel eggs are eight foot tall stone statues that are decorated with mystical, ancient carvings. Their main role is to guard the warren and naturally also the tunnels, which googies use to be delivered on the surface, aside of the job that they have to protect the smaller eggs.
The main inspirtion for the sentinels were inspired by various myths and legends that are/were in close relationship with the nature - if you look closely to them you'll see Native American totems, celtic forest gods, Japanese Buddhist forest spirit - and all these have in comon is the protection of sacred and natural places.
These giant moving statue eggs have rotable heads, which can show three different expressions: neutral, freaked out and angry. This helps them to ward off the intruders and protect both the warren and the googies. They also serve as storage for the smaller eggs, one sentinel can have around 300 of googies stored in its hollow areas.
We were leaning toward more European vegetation, like pine trees and bluebells, rather than orchids and other tropical flowers intentionally, because each realm represents a meddling of different regions of the earth"
- Boas; p 47 of The art of Rise of The Guardians
The Book warren comes to be described completely different from what is the movie warren, while it has loads of tunnels, it's main entry is at Easter Islands. When North and Katherine are brought in the deeps, they pass lot of rooms that are all egg-shaped. The book Bunnymund is actually obsessed with the egg-shape, he also says that it was a shame that he had to remodel earth from the egg shape to this circular boring thing. Most egg chambers are equipped for making chocolate. Then there are also some chambers that seem some kind of egg museums, from jewels to natural eggs. And then there is the chamber of the relic, the egg that North and Katherine were searching.
But the next chamber they found themselves in was kind of egg museum. There were shelves upon shelves of intricately crafted, jewel-encrusted eggs
- p.165 in E.Aster Bunnymund and the Warrior eggs at the earth's core!
To move in the tunnels, and to go to the earth's core, Bunnymund uses an egg-shaped train, because in the book world, when it comes to Bunny, everything is egg-shaped.
Another difference is the warrior eggs, they come in various sizes with various weapons.
The smallest eggs were the size of common chicken's egg, while platoons of other eggs were nearly as big as a good-sized suitcase, and surprising number of eggs were huge - more than ten feet tall.
- p.189 in in E.Aster Bunnymund and the Warrior eggs at the earth's core!